Obviousness

Obviousness Analysis of U.S. Patent 7,279,708 under 35 U.S.C. § 103

This analysis evaluates whether an invention claimed in U.S. Patent 7,279,708 would have been obvious to a Person of Ordinary Skill in the Art (POSA) at the time the invention was made (circa 2004-2005). An invention is obvious if the differences between the claimed invention and the prior art are such that the invention as a whole would have been obvious to a POSA.

The key inventive concept in the '708 patent is the creation of vents in a sub-conductive layer to allow for the outgassing of an underlying organic insulating layer during the manufacturing of an electroluminescent (EL) display. This sub-conductive layer's primary purpose is to electrically connect a power supply line to the device's second electrode (cathode). The vents are realized either as "penetration portions" (holes) in a continuous layer (Claim 1) or as gaps between "unit sub-conductive layers" (Claim 9).

Primary Obviousness Combination: US 2005/0200270 A1 (Kwak) in view of General Knowledge of Outgassing

A strong argument for obviousness can be made by combining the teachings of the inventor's own prior art application, Kwak, with the well-established knowledge in the art regarding the problems of outgassing from organic materials during vacuum processing.

1. Scope and Content of the Prior Art:

• US 2005/0200270 A1 ("Kwak '270"): Filed over a year before the '708 patent, Kwak '270 discloses the core electrical architecture of the invention. It teaches an EL display with an "auxiliary electrode" (the '708 patent's "sub-conductive layer") that connects a power line to the cathode to reduce voltage drop. This auxiliary electrode is formed of the same material as the pixel anodes and is situated on top of an insulating layer, connecting to the power line through a via hole. Kwak '270, however, depicts this auxiliary electrode as a solid, continuous layer, making no mention of outgassing or any need for perforations.

• General Knowledge in the Art (circa 2004): It was widely known in the semiconductor and display manufacturing fields that organic materials, such as the acryl or benzocyclobutene (BCB) used for planarization/insulating layers, release trapped solvents, water vapor, and other gaseous byproducts (i.e., they "outgas") when heated or placed under vacuum. This outgassing was a known cause of manufacturing defects, such as delamination ("peeling") or "bubbling" of overlying films if the gas was trapped. The '708 patent itself acknowledges this issue in its background section.

2. Differences Between Prior Art and Claims:

The primary difference between the structure taught in Kwak '270 and the claims of the '708 patent is the modification of the sub-conductive layer to facilitate gas escape.

• Claim 1: Adds the limitation that the sub-conductive layer includes a "penetration portion."
• Claim 9: Adds the limitation that the sub-conductive layer comprises a plurality of "unit sub-conductive layers" that are "separated from each other."
• Claims 11 & 15: Recite the methods of making the structures of claims 1 and 9, respectively.

3. The Person of Ordinary Skill in the Art (POSA):

A POSA in this field would be an engineer or scientist with experience in OLED/EL display design and fabrication, including thin-film deposition, photolithography, and vacuum processing. This person would be familiar with the properties of materials used in display manufacturing, including the outgassing characteristics of organic polymers.

4. Motivation to Combine and Expectation of Success:

A POSA seeking to implement the improved electrical connection taught by Kwak '270 would recognize that placing a large, continuous auxiliary electrode over an organic insulating layer would create a new problem: it would act as a cap, trapping gas released from the organic layer during subsequent high-temperature or vacuum deposition steps. This trapped gas would foreseeably lead to defects, lower manufacturing yields, and increased processing times needed for outgassing around the edges of the layer.

Faced with this predictable problem, the motivation to modify the structure would be immediate and self-evident: to create a path for the gas to escape. The solutions claimed in the '708 patent represent simple, predictable, and obvious design choices to achieve this goal:

• Creating "penetration portions" (Claim 1): The most fundamental and common-sense method for venting a trapped gas through a barrier is to create holes in that barrier. A POSA would have found it obvious to pattern a series of holes or slits in the sub-conductive layer to allow the gas to vent vertically.
• Creating "separated" unit layers (Claim 9): An alternative, equally obvious approach would be to not form the conductive layer as a continuous sheet in the first place. By patterning it as an array of smaller, distinct pads or strips, gaps are naturally created between them, which would serve as effective channels for the gas to escape.

In both cases, there would be a high expectation of success. A POSA would know that creating such openings would relieve the gas pressure without significantly compromising the primary electrical function of the sub-conductive layer, provided the perforations or gaps were not excessively large.

Conclusion:

The independent claims of U.S. Patent 7,279,708 would have been obvious to a person of ordinary skill in the art at the time of invention. The prior art, particularly Kwak '270, taught the essential electrical structure. The claimed improvement—adding vents to this structure—is an obvious solution to the well-known and predictable problem of outgassing from the underlying organic insulating layer. The specific methods of venting recited in the claims (holes or separated pads) are basic, common-sense design choices that a skilled engineer would readily employ to solve this known manufacturing issue.